The 21st International Neurotoxicology Conference (NTX XXI) will be held Feb. 10-14, 2004 at the Ala Moana hotel in Honolulu, Hawaii. NTX XXI will address the theme Infant and Child Neurotoxicity Studies: Subtle and Long-Term Effects. Studies will focus on methylmercury (MeHg), PCBs, heptachlor, other persistent pollutants and mixtures. The highlight of this conference is that all the major longitudinal children's studies addressing these important pollutants will be presented together for the first time! This will allow a unique opportunity to make significant advances in our understanding of the subtle and latent effects that these chemicals -alone or in combination-may be posing to our children. Justification for Hawaii Venue: Results of two major research efforts involving Hawaiians and others from the Pacific Rim will be presented for the first time at this conference. These two major themes require the meeting to be held on Oahu. The two areas are: (1) The Hawaii Heptachlor Study (20-yr study results) and (2) Persistent Pesticides and the Honolulu-Hawaii-Asia Aging Cohort. The Hawaii Heptachlor Research and Education Foundation promised Hawaiian citizens that the results of the Heptachlor Children's Study first would be reported to the Hawaiian community. The last day of the conference will be a "Report Back to the Community" in a Public Session devoted to the Hawaii Heptachlor Study 20 years after the initial pollution. Specific Aims: (1) To provide an internationally recognized, interdisciplinary scientific forum for presentation of the major longitudinal children's studies investigating the low-level, long-term effects of MeHg, PCBs, lead, heptachlor, other pesticides and mixtures. (2) To conduct an Open Public Forum/Town Meeting for clinical and basic scientists, clinicians and the citizens of Hawaii who were involved in the 20-year Heptachlor studies. To facilitate communication between the researchers, and the parents & children from Hawaii who were exposed to Heptachlor to discuss the implications of study results. (3) To convene scientists from different sectors to exchange data and theories regarding the etiology, mechanisms, diagnosis, treatment and prevention of environmentally-induced diseases or disorders of the nervous system in the fetus, infant, child, adolescent, and latent effects in the adult. To provide an established venue and ample time for informal scientific exchange to establish and promote collaborations and networking worldwide. (4) To encourage, mentor and recognize student researchers and young neurotoxicologists by offering pre-doctoral and post-doctoral awards (cash and plaques, travel scholarships, mentoring and networking opportunities. (5) To organize the keynote presentations, tutorials, invited and free presentations, discussions, demonstrations and interactions to document, major new research advances, facilitate identification of specific research gaps and potential experimental designs to answer questions. (6) To rapidly peer review and disseminate findings to the scientific community. The overall goal will be accomplished by organizing and conducting a five-day widely-advertised and well-organized conference according to the format of previous conferences in this well-established Neurotoxicology Conference series which has proven to be very successful. All presenters are invited to submit original research papers of new data presented and/or summaries of recent findings related to the specific topics in the Program. Papers will be peer-reviewed and rapidly published (less than one year) in Neurotoxicology, an international scientific journal that is widely disseminated, indexed, abstracted and available online.